Molecular and cellular analysis of human asthma

Asthma is a respiratory disorder characterized by reversible airflow limitation, bronchial hyperresponsiveness, and airway inflammation. A prominent subset of asthma is characterized by type 2 inflammation in which the pro-inflammatory type 2 cytokines (IL-13, IL-5, and IL-4) are key pathogenic factors leading to the recruitment and activation of various immune cell types. Infiltration of T-helper type 2 (Th2) cells to the airways and lung parenchyma coordinates with tissue-resident innate lymphoid cells (ILC2) to recruit myeloid cells to the airways. 

To characterize cell types that contribute to asthma pathogenesis, we immunophenotype cells in blood, bronchoalveolar lavage (BAL) fluid, and induced sputum by flow cytometry (FACS) and mass cytometry (CyTOF). These studies are conducted in close collaboration with our friends and colleagues in the UCSF Airway Clinical Research Center.

Figure: Characterization and sorting of enriched T-helper cell subsets and rare ILC2s in asthma


We also investigate miRNA regulation of the cell types involved in type 2 immunity, specifically eosinophils, basophils, mast cells, ILC2s, and naïve and memory T-helper cells (Th1, Th2, Th17, Tfh). By sorting each of these cell types from human or mouse biospecimens, we profile their miRNA expression, and have identified differentially expressed miRNAs in airway T-helper cells in asthma. We profile miRNA expression using a high-throughput multiplex qRT-PCR platform (Fluidigm Biomark). To understand the roles of specific miRNAs in regulating the function of these cell types we perform downstream functional analyses such as allergic airway inflammation models and T-helper cell differentiation assays.

Figure: miRNA expression in airway-infiltrating CD4 T cells in human asthma